1. Field of the Invention
The present invention relates to phase detection apparatuses, and more particularly, to a phase detection apparatus that can accurately detect a phase difference between an input signal and a reference signal even though the input signal and the reference signal have different duty cycles.
2. Description of the Related Art
Recently, liquid crystal display (LCD) products have come into widespread use because they are small, lightweight, and thin. Backlight units that supply light are used in the LCD products. The LCD products use lamp driving signals for controlling the driving of lamps in the backlight unit, and horizontal and vertical synchronization signals used for images of the LCD.
If interference occurs between the lamp driving signal and the horizontal and vertical synchronization signals that are used in the LCD product, the screen shakes, and that is called a “waterfall”. In order to prevent this waterfall on the screen, a phase detector is used to synchronize the signals used in the LCD product with a predetermined reference signal such that the interference between the lamp driving signal and the horizontal and vertical synchronization signals can be avoided.
However, according to the related art, when a phase detector detects a phase difference between an input signal and a reference signal, if the input signal and the reference signal have different duty cycles, the phase detector detects a phase difference corresponding to a duty-cycle difference between the input signal and the reference signal even through the input signal and the reference signal are synchronized with each other.